Multidrug-resistant strains of many clinically important pathogenic bacteria, including methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pneumoniae, Mycobacterium tuberculosis, and Enterococci strains are becoming a worldwide health problem. There is an urgent need to discover new agents to treat patients infected with multidrug-resistant bacteria. A new group of thiazolyl peptide antibiotics, (designated herein as nocathiacins) having inhibitory activity at the nanomolar level against Gram-positive bacteria has been discovered. The present invention relates to novel antibiotic halo- or hydroxy-substituted nocathiacin compounds, and comprising the process for preparing them by precursor-directed biosynthesis with Nocardia sp. ATCC-202099 or mutants thereof. The novel nocathiacin antibiotics disclosed herein exhibit potent antimicrobial activity against Gram-positive bacteria in vitro, and exhibit in vivo efficacy in a systemic Staph. aureus infection model in animals. The nocathiacin compounds are antibiotics useful in the treatment of bacterial infections in humans.